This patent specification is in the field of exercise machines and methods. It relates more specifically to equipment and exercises designed to enhance performance in activities such as running, jumping and the like but also has a broader application.
Various types of exercise machines are used to enhance athletic performance and promote health and well-being, for medical tests and treatment, for rehabilitation after injury or illness, for elder care, and for other purposes. It is believed that the use of such equipment is growing, both in public facilities such as sports clubs and at home.
Known exercise machines typically focus on particular muscle groups and typically require acting against gravity or spring action. With gravity-based machines, as with free weights, the user moves and accelerates/decelerates a mass against gravity. Because of the forces involved and the nature of the exercises, inertia is a significant limiting factor, resisting or even precluding rapid changes in direction and speed. This in turn typically makes it impractical and even dangerous to do exercises such as those simulating the fast, explosive movements many sports value. Too fast a movement or change in direction with gravity-based machines can generate inertia forces so high that they dramatically increase the opposing forces and can injure the user. As a result, users of gravity-based equipment or free weights are constrained to relatively slow movements, and an adage of many trainers is xe2x80x9cup in three, down in fourxe2x80x9d (counts).
Examples of such gravity-based exercise machines are available from many companies. One is equipment from Nautilus and another is proposed in U.S. Pat. No. 5,941,804 and involves simulating running by using weights 38 mounted on hubs 37 and a gas-charged (or similar) lift support 47. Similar considerations apply to exercise machines that rely on spring action provided by coil or leaf springs or rubber bands or belts instead of weights.
Other types of exercise machines use brake pads or other braking systems to provide resistance to movement. One example is proposed in U.S. Pat. No. 3,953,025, where brake pads press against a disc that the user rotates in arm-training (FIG. 1) or leg-training (FIG. 11). The degree of resistance is said to be adjustable by turning a knob that changes the force with which the pads press against the disc (and thus the braking force). However, this does not appear to provide a practical way to customize resistance to the needs of individual users and exercises, or to vary resistance during a movement, or to control resistance in ways that are repeatable or easily measurable. More controlled resistance to movement can be provided with an electrohydraulic system, as proposed in U.S. Pat. Nos. 4,726,583 and 4,354,676, where the user can push or pull a piston moving in a cylinder containing fluid that exits through a control valve at a desired flow rate. U.S. Pat. No. 4,544,154 proposes an exercise machine using feedback to control the resistance of a hydraulic cylinder. The last three patents are hereby incorporated by reference. Exercise machines that incorporate electrohydraulic cylinders and computer controls to selectively vary the resistance to user movement have been placed in public use at the Private Training Centers, 2300 Santa Monica Boulevard, Santa Monica, Calif., under the trade name VERT.
Various types of machines directed specifically to running exercises also have been proposed. One common type uses a moving belt on which the user runs. The belt can be horizontal or can be inclined at a selected angle to simulate running uphill. Another type is proposed in U.S. Pat. No. 5,941,804, hereby incorporated by reference, involves placing the user""s shoulders against a harness and the user""s legs in foot assemblies that move against gravity acting on weights. As with other gravity-based machines, inertia is a factor that can make it impractical to simulate the fast, explosive movements common in sports such as football, basketball and in many other activities.
An object of the system disclosed in this patent specification is to provide exercise equipment useful for improving starting strength, acceleration and overall strength in a safe, convenient and particularly effective manner, and to provide a system that is versatile and can be easily adapted to different users, exercises and goals.
Overall strength can be important in many activities, and starting strength and acceleration can be paramount in others. Starting strength in running can be thought of as the strength needed for the first few of steps of a race or other running activity. Starting ability is related to reaction time and explosive strength or power. Acceleration in this context can be thought of as the ability to rapidly come up to the highest speed attainable under the circumstances. In some sports such as the 100-meter dash, the athlete may come up to a maximum attainable speed over tens of meters, and the body angle may change during that time. In other sports such as football or basketball the players often do not attain their absolute maximum speeds, for example because the spurts of running are too short. The body angle still may change during the rapid acceleration and deceleration, or may change in different ways. For these and other reasons, it can be more important to train for the maximum speed attainable over shorter distances and at different body angles, instead of or in addition to training for an absolute maximum attainable speed.
In one embodiment the system disclosed in this specification provides an exercise system in which a support frame maintains a shoulder harness and foot pedals at adjustable, selected positions relative to each other. This adjustability enables users of different body sizes and planning different exercise regimes to fit comfortably and at the desired body angle when they place their feet at the foot pedals and shoulders against the shoulder harness. The shoulder harness preferably includes a chest support that can be placed at a selected angle and height to match a particular user and particular exercises.
To provide a particularly wide choice of exercise regimes, the foot pedals act on respective bi-directional, variable resistance elements that are under computer control. In this example of an embodiment, the pedals connect to the resistance elements through direction-reversing levers pivoted about an upper portion of the support frame. Under precise and repeatable computer control, the resistance elements offer selected, well controlled degrees of force opposing motion and acceleration, preferably independently in each direction and for each foot pedal and even during a motion stroke. The resistance elements can be fluid-filled cylinders, each having a piston moving therein against fluid pressure that can be changed rapidly under computer control, before or during the exercise or during particular motions, by changing the rate of flow of fluid in or out of the cylinders or portions thereof.